Stop failing to notice the log says "Reusing connection to server:80" before the breakage.
Realize that's the HTTP keep-alive feature, which wget already has an option to disable.
Find the option to disable; make winget set it; find it doesn't work.
Realize the C++ winget code and the C code have different struct options opts, and the option wasn't set after all.
w00t and celebrate a successful concurrent download before thinking about how to unify the opts, since after all that's an implementation detail, an opportunity for learning, a growing experience, and everything else you can afford to call something hard when you have the luxury of a good mood to go with it.